1. Field of the Invention
The present invention relates generally to switching devices, and in particular to an improved electromagnetic relay.
2. Description of the Prior Art
In the prior art, there is known an electromagnetic relay of the hinge-type, as disclosed in Japanese Utility Model Laid-Open Publication No. 56-170852, in which the switching operation of the relay is achieved by the swinging operation of an armature generated on the basis of excitation or deexcitation of the electromagnet. In this device, the contact surface of a movable contact plate of a yoke and/or armature in the contact portion at which the armature contacts with the yoke is beveled.
According to the conventional electromagnetic relay, since the contact surface of a movable contact plate of the yoke and/or armature in the contact portion at which the armature contacts with the yoke is beveled, the magnetic path is made narrow at the beveled portion thereby undesirably reducing the efficiency of the magnetic circuit. In accordance with the efficiency reduction, the suction force due to the coil is also reduced thereby generating an insufficient suction force for the armature. The reduced suction force results in problems such that the minimum operation voltage of the electromagnet is increased, and the so-called two-step operation phenomenon of the relay is generated, whereby a sufficient contacting pressure is not maintained.